Refactor: Build: Add bf::dependencies::eigen target

To make adding a dependeny on TBB easier.

Additional changes:
* Using LIB for libmv tests, as it now brings in includes
* Removing Eigen header listing in iTaSC

Pull Request: https://projects.blender.org/blender/blender/pulls/136865

intern/eigen/CMakeLists.txt

@@ -7,7 +7,6 @@ set(INC
 )
 
 set(INC_SYS
-  ${EIGEN3_INCLUDE_DIRS}
 )
 
 set(SRC
@@ -25,6 +24,7 @@ set(SRC
 )
 
 set(LIB
+  PRIVATE bf::dependencies::eigen
 )
 
 if(WITH_OPENMP AND WITH_OPENMP_STATIC)